source: trunk/src/gui/widgets/qsizegrip.cpp@ 986

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#include "qsizegrip.h"

#ifndef QT_NO_SIZEGRIP

#include "qapplication.h"
#include "qevent.h"
#include "qpainter.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qlayout.h"
#include "qdebug.h"
#include <QDesktopWidget>

#if defined(Q_WS_X11)
#include <private/qt_x11_p.h>
#elif defined (Q_WS_WIN)
#include "qt_windows.h"
#endif
#ifdef Q_WS_MAC
#include <private/qt_mac_p.h>
#endif

#include <private/qwidget_p.h>
#include <QtGui/qabstractscrollarea.h>

#define SZ_SIZEBOTTOMRIGHT  0xf008
#define SZ_SIZEBOTTOMLEFT   0xf007
#define SZ_SIZETOPLEFT      0xf004
#define SZ_SIZETOPRIGHT     0xf005

QT_BEGIN_NAMESPACE

static QWidget *qt_sizegrip_topLevelWidget(QWidget* w)
{
    while (w && !w->isWindow() && w->windowType() != Qt::SubWindow)
        w = w->parentWidget();
    return w;
}

static inline bool hasHeightForWidth(QWidget *widget)
{
    if (!widget)
        return false;
    if (QLayout *layout = widget->layout())
        return layout->hasHeightForWidth();
    return widget->sizePolicy().hasHeightForWidth();
}

class QSizeGripPrivate : public QWidgetPrivate
{
    Q_DECLARE_PUBLIC(QSizeGrip)
public:
    void init();
    QPoint p;
    QRect r;
    int d;
    int dxMax;
    int dyMax;
    Qt::Corner m_corner;
    bool gotMousePress;
    QWidget *tlw;
#ifdef Q_WS_MAC
    void updateMacSizer(bool hide) const;
#endif
    Qt::Corner corner() const;
    inline bool atBottom() const
    {
        return m_corner == Qt::BottomRightCorner || m_corner == Qt::BottomLeftCorner;
    }

    inline bool atLeft() const
    {
        return m_corner == Qt::BottomLeftCorner || m_corner == Qt::TopLeftCorner;
    }

    void updateTopLevelWidget()
    {
        Q_Q(QSizeGrip);
        QWidget *w = qt_sizegrip_topLevelWidget(q);
        if (tlw == w)
            return;
        if (tlw)
            tlw->removeEventFilter(q);
        tlw = w;
        if (tlw)
            tlw->installEventFilter(q);
    }

    // This slot is invoked by QLayout when the size grip is added to
    // a layout or reparented after the tlw is shown. This re-implementation is basically
    // the same as QWidgetPrivate::_q_showIfNotHidden except that it checks
    // for Qt::WindowFullScreen and Qt::WindowMaximized as well.
    void _q_showIfNotHidden()
    {
        Q_Q(QSizeGrip);
        bool showSizeGrip = !(q->isHidden() && q->testAttribute(Qt::WA_WState_ExplicitShowHide));
        updateTopLevelWidget();
        if (tlw && showSizeGrip) {
            Qt::WindowStates sizeGripNotVisibleState = Qt::WindowFullScreen;
#ifndef Q_WS_MAC
            sizeGripNotVisibleState |= Qt::WindowMaximized;
#endif
            // Don't show the size grip if the tlw is maximized or in full screen mode.
            showSizeGrip = !(tlw->windowState() & sizeGripNotVisibleState);
        }
        if (showSizeGrip)
            q->setVisible(true);
    }
};

#ifdef Q_WS_MAC
void QSizeGripPrivate::updateMacSizer(bool hide) const
{
    Q_Q(const QSizeGrip);
    if (QApplication::closingDown() || !parent)
        return;
    QWidget *topLevelWindow = qt_sizegrip_topLevelWidget(const_cast<QSizeGrip *>(q));
    if(topLevelWindow && topLevelWindow->isWindow())
        QWidgetPrivate::qt_mac_update_sizer(topLevelWindow, hide ? -1 : 1);
}
#endif

Qt::Corner QSizeGripPrivate::corner() const
{
    Q_Q(const QSizeGrip);
    QWidget *tlw = qt_sizegrip_topLevelWidget(const_cast<QSizeGrip *>(q));
    const QPoint sizeGripPos = q->mapTo(tlw, QPoint(0, 0));
    bool isAtBottom = sizeGripPos.y() >= tlw->height() / 2;
    bool isAtLeft = sizeGripPos.x() <= tlw->width() / 2;
    if (isAtLeft)
        return isAtBottom ? Qt::BottomLeftCorner : Qt::TopLeftCorner;
    else
        return isAtBottom ? Qt::BottomRightCorner : Qt::TopRightCorner;
}

/*!
    \class QSizeGrip

    \brief The QSizeGrip class provides a resize handle for resizing top-level windows.

    \ingroup mainwindow-classes
    \ingroup basicwidgets

    This widget works like the standard Windows resize handle. In the
    X11 version this resize handle generally works differently from
    the one provided by the system if the X11 window manager does not
    support necessary modern post-ICCCM specifications.

    Put this widget anywhere in a widget tree and the user can use it
    to resize the top-level window or any widget with the Qt::SubWindow
    flag set. Generally, this should be in the lower right-hand corner.
    Note that QStatusBar already uses this widget, so if you have a
    status bar (e.g., you are using QMainWindow), then you don't need
    to use this widget explicitly.

    On some platforms the size grip automatically hides itself when the
    window is shown full screen or maximised.